Piston-ring expander



April 2l, 1931. .1. H. TRINDL PISTON RING EXPANDER Filed April 8, 1929 2Sheets-Sheet l Ver; DEL

APl 21, 1931. J. H. TRINDL BIsToN RING EXPANDER Filed April 8, 1929 2Sheets-Sheety 2 Patented Aipr. 2l, 1931 JOSEPH n. Tamm, or Arianne,ILLINOIS Y rIsroN-me nxeannnn.

Application filed April 8,

This invention relates to a piston ring expander and particularly to onehaving compound radial and axial movements for caus-` ing a piston ringto conform to the cylinder wall throughout the piston travel,irrespective of the condition of the cylinder wall, to effect tightsealing between the piston and. cylinder walls at all engine speeds.

An object of the invention is to provide a m piston ring expander whichwill expand axially and radially within the piston ring i groove.

Another object of the invention is to provide a piston ring expander ofsimple con- '15 struction which will urge the ring in. constantlytightengagement with the cylinder wall and also 'a side wall of the ringgroove to prevent gas or liquid leakage to. pass the rin object is toprovide an expander forlflexible piston rings which is so construted 'asto be instantly responsive to any irregularities inthe cylinder walls toiex the rings against the wall in sealing engagement. The above, furtherand other objects of the invention will beapparent from the followingdescription, accompanying drawings, and appended claims. The inventionis exemplified in the accompanying drawings and the views thereof are asfollows:

Figure lis a fragmental vertical section `through a portion of acylinder and piston having the piston rings supported in expandersembodying this invention.

Figure 2 is a transverse section through a piston supplied with a pistonring and expander embodying this invention.

Figure 3 is an enlarged fragmental top plan view of a portion of oneform of expander.

'Figure 4 is a side elevational view of one form of the expander.

Figure 5 is a top plan view of one form of the expander.

'Figure 6 is a view similar to Flgure 1 showing a modied form ofexpander lnserted 1n the piston ring grooves for supportmg the pistonrings.

I0 Figure 7 is a transverse sectional v1ew 1929. Serial No. 353,369.

through a piston provided with an expander of the modiiied formillustrated in Figure 6.

Figure 8 is an enlarged fragmentary top plan view of an expander of themodified form. v

Figure 9 is an elevational view of a piston ring expander of themodified form.

Figure 10 is a top plan view of the ring 'illustrated in Fi ure 9.

As shown on t e drawings:

Figure 1 includes a cylinder 1, a top casting 2, and a piston 3. Thepiston is provided with ring grooves 4 having oil ducts 5 Openin intothe interior of the piston.

he piston is provided with the usual wrist pin 6 and connectin rod 7. Abearing 8 is interposed between t e wrist pin 6 and the connecting rod.

The piston ring expander illustrated in Figures 1 through 5 inclusive ofthe drawings, consists of a split ring which is substantially rightangled in cross-section, and includes an upstanding flange 9 and ahorizontal ange 10.

A plurality of lugs or projections 11 are struck inwardly from. theupstanding flange 9. The lugs 11 are shown as arranged 1n pairs with thesame extending in opposite directions as illustrated. Similar lugs orprojections 12 are struck downwardl from the horizontal flange 10 andprefera ly are arranged in pairs extending in opposite directions, as sown. However, the lugs may be arranged in any other manner than shown,if desired.

The expander is made of thin resilient metal consequently the lugs 11and 12 struck therefrom are resilient and serve as spring fingers foracting on the expander and its piston ring.

The several expanders are inserted in the ring grooves 4 of the piston 3for supporting flexible piston rings 13 in said grooves. The tendency ofthe expanders is, to urge the rings 13 radially outwardly and axiallyupwardly,` thus maintaining the piston rings in tight engagement withthe piston wall and the upper walls of the ring grooves.

An expander of this sort maintains the ring in tlght engagement with thecylinder 10 wall irrespective of any irregularity in its shape and alsomaintalns the ring tightly against the upper wall of the groove, thustightly sealing the ring groovein radial and axial direction against gasand liquid leakage. Furthermore, the expander being provided with thespring lugs 11 and 12 prevents pumping action of the ring in service,thus eectively sealing the piston within the cylinder.

The form of the invention illustrated in Figure 6 through 10 of thedrawings, discloses a cylinder 1, a top casting 2, and a piston 3 with awrist pin 6, connecting rod 7, and wrist pin bearing 8. The piston 3 isprovided with the usual piston ring grooves 4 which grooves are shown asprovided with oil ducts 5.

The expander of this form of the invention is similar to thatillustrated in Figures 1 through 5 of the drawings in that it consistsof anupstandin flange 14 and an outwardly directed radial ange 15. Thisring, also, is s lit.

pThe radial flange 15 is providedfwith downwardly extending spring lugs16 formed by depressing portions of the metal of the iange 15 to formthe lugs.

The upstanding flange 14 is provided throughout its extent with aplurality of inwardly directed indentations 17 formed by drawing themetal of the flange 14 to provide the indentations.

The indentations 17 of the upstanding iange 14 are in ei'ect springmembers as the expander is made of thin spring metal. Such indentations17 serve to center the expander in the piston ring groove and also tendto urge the expander radially of the piston, while the lugs 16 tend tourge'the expander axially of the piston.

The indentations 17 may, of course, be pressed inwardly or outwardly ofeither of the flanges of the expander and will be made as long and onsuch curves as will produce a satisfactory spring effect when theexpander is in use.

A piston rin 18 (is supported in an expander of this rm of the inventionand is urged radially outwardly by reason of the spring indentations 17and axially upwardly by reason of the spring lugs 16 depending from theradial ange 15 of the expander.

This form of the invention urges the ring radially outwardl as well asaxially of the piston, thus effectively sealing the piston in thecylinder.

A perfect piston ring requires free radial movementfof the ring whichmust be sufficient to allow the ring to conform to the cylinder wall atall speeds of the engine. A The ring grooves increase in width inservice and the piston rings must be supported in such manner as tocompensate for such wear and must also form an eective seal to preventoil pumping, causedby movement axially of the ring in the ring groove.

The piston ring expander if this invention, by reason of the compoundaction thereof, in urging the piston outwardly radially of the pistoncauses the ring to conform to the cylinder Wall, and also the axialmovement imparted to the ring by the spring lugs depending from theradlal ianges of the expanders maintains the piston ring against theupper side wall of the piston ring groove to ei'ectively seal the same.The lugs struck from the radial flanges of the expander prevent movementof the piston ring within the piston ring groove, thus eliminatingobjectionable oil pumping.

There are enough of the lugs and indentations provided on the pistonring expander of this invention to effectively maintain the piston ringsat all times in tight engagement with the cylinder wall even thoughirregular, as well as with the wall of the piston ring groove.

The provision of the lugs 11 in the upstanding wall 9 of the form shownin Figures 1 through 5 and the indentation 17 formed in the upstandingwall 14' of the modification, serve to center the piston rings in thepiston ring grooves as well as having the tendency to normally urge thepiston rings radially outwardly of the piston into tight engagement withthe cylinder walls.

The piston,y rings are flexible as are the piston ring expanders, andbecause of the provision of the suliicient number of lugs, the pistonrings are maintained in tight engagement with the cylinder wall nomatter how badly the same is worn.

The gist of this invention resides in the provision of the piston ringexpander comprising a split thin metal spring ring having projectionsfor exerting spring action radially and axially of the piston.

The expanders may be arranged, if desired to urge the piston ringsradially outwardly and axially downwardly as well as upwardly.

The expander of this invention may be used with compression rings aswell as with oil rings.

This invention contemplates expanders in which the spring fingers orlugs are directed outwardly of the axial flanges and upwardly from theradial ianges, that is with the {ingers or lugs in direct contact withthe piston rings instead of in contact with the ring grooves in thepiston as in the forms illustrated in the drawings.

The form of lugs shown at 17 in Figures 8, 9, 10 and 11 as in the axialflange might of course be used in the radial iange of the expanders, inwhich event the lingers in the axial ange would be open at one end asshown at 16 in Figure 9. In other words the fingers 16 and 17 would beinterchanged as to the expander flanges.v

. expander ilanges/ The invention has been described herein, more orless precisely, yet it is to be understood that changes may be made inarrangement and proportion of parts and that equlvalents may besubstituted without departing from the spirit and scope of theinvention.

I claim as my invention:

l. A piston ring expander having projections for urging the rin radiallyoutwardly and other proJectings or urging the ring axially. y

2. A piston expandercomprising a split ring of spring metal formed withan axial llange and a radial flange, said flanges having inwardly anddownwardly directed spring fingers respectively struck from saidflanges.

`3. A piston rin expander comprising a split ring of an ar form havingan axial ange and a radial flange, said axial ange having inwardlyextending portions struck therefrom for normally urging said ringradially outwardly when inserted in a piston ring groove.

4. A piston ring expander comprising an angular split ring of thinmetal, said ring having an axial flange and an outwardly directed radialflange, said radial flange having downwardly extending projectionsstruck therefrom for normally urging said expander toward a wall of apiston ring groove when l said expander is inserted in said groove.

5. A piston ring expander comprising a split ring of angularcross-section having an axial iange and a radial ange, projectlonsstruck inwardly from said axial iange, projections struck downwardlyfrom said-radial ange, said projections acting as spring fingers to urgesaid expander radially outwardly and axially upwardly when said expanderis inserted in a piston ring groove.

6. A piston ring expander comprising a split vring of angularcross-section having an axial flange and a radial flange, projectionsstruck from said axial lange, projections struck from said raidialflange, said projections acting as spring fingers to urge said expanderradially outwardly and axially when said expander is inserted in apiston ring groove.

7. A piston ring expander of spring metal having means struck from thebody for urging the same radially and axially.

8. A piston.v ring expander of. spring metal having lingers thereon forurging the same radially and axially.

9. A piston ring expander of flanged spring metal having means on thethereof for urging the same radially and axially.

10. A piston ring expander having axial and radial flanges, portions ofsaid flanges being struck therefromv to form springs for urging saidexpander axially and radially.

11. A piston ring expander having pro- )ections struck therefrom andeffective for moving said expander and its associated piston ringaxially and radially.

12. A piston ring expander of substantially circular outline andsubstantially right angled in cross section, said expander havingportions formed from the body of the same and deiected with respect tosaid body for acting as spring members for causing radial and axialmovement of the-ring supported by said expander.

In testimony whereof I have hereunto subscribed my name at Chicago, CookCounty,

Illinois.

JOSEPH H. TRINDL.

